Gas turbine engines typically include a fan delivering air into a compressor. The air is compressed in the compressor and delivered into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine blades, driving them to rotate. Turbine rotors, in turn, drive the compressor and fan rotors. A turbine section typically includes multiple stages of vanes and rotor blades use to extract a maximum amount of energy from the combustion flow. The efficiency of the engine is impacted by ensuring that the products of combustion pass in as high a percentage as possible across the turbine blades.
With each new engine design, gas temperatures increase and cooling flow requirements decrease. This requires cooling flow to be utilized in a more efficient manner and flow distribution to be tailored to prevent overcooling in certain regions. A radial variation in gaspath pressure at a trailing edge of an airfoil can result in excess cooling flow for current trailing edge configurations. The supply pressure for trailing edge slots is set such that a backflow margin (pressure ratio across the slots) meets minimum requirements. This supply pressure is relatively constant for all of the trailing edge slots, while the gaspath exit pressure can vary radially, resulting in some slots with higher backflow margins. Since the trailing edge slot sizes are determined by manufacturing requirements, this results in some slots having higher cooling flows.